Non-Invasive Devices to Suppress Tremors
For some people with Parkinson’s disease (PD), medication doses treat their tremor very well. However, for others, medication doses are clearly effective for symptoms of slowness and stiffness, but they are ineffective for their tremor. In these cases, deep brain stimulation (DBS) or focused ultrasound may be suggested to help a tremor that seems resistant to medication.
A different approach that is being developed for people with tremors of all kinds (not just PD), is the use of non-invasive, wearable medical devices that can suppress tremor. Over the past few years, a number of devices with different mechanisms of action designed to suppress tremor have been developed.
What is the Science Behind These Devices, and Do They Work?
Today, I will explore this type of equipment and its use in PD. Of note, there are many different products currently in the development pipeline that are attempting to tackle this problem. Some of the products have reached a point at which they are available for purchase, but there are many other devices in development that have not reached this stage.
For those looking for more detailed information, Biosensors medical journal published an article that is a great resource for devices currently on the market or being developed.
Will Insurance Cover Wearable Devices for Parkinson’s Tremor?
Most devices mentioned in this post are unfortunately not covered by insurance. These devices typically will cost in the hundreds of dollars out of pocket. Some of the manufacturers will offer financial assistance and/or payment plans.
Many manufacturers will allow you to try out their devices and return them for a refund (some offer a complete refund, and some do not) if you are not satisfied with the results.
How Do Wearable Tremor-suppression Devices Work?
Transcutaneous electrical nerve stimulation
In this type of system, electrical stimulation is applied to the skin’s surface to stimulate the sensory nerves, the nerves that carry information about pain, temperature, and body positioning from the limbs to the brain. The exact mechanism of how this stimulation suppresses tremor is not completely worked out. It is known that sensory nerves connect from the arms and legs to a part of the brain called the thalamus, which is also implicated in tremor. It is thought that stimulating the sensory nerves can disrupt pathological circuits in the thalamus that are responsible for tremor.
Cala One was the first transcutaneous electrical nerve stimulation system approved by the FDA in 2018 for tremor control. A newer version, Cala TrioTM, is designed to replace Cala One. Cala-Trio is FDA-cleared and is available with a prescription from your doctor. The device is worn on the wrist and applies electrical stimulation to the median and radial nerves. Of note, someone with a DBS system in place is not able to use Cala One or Cala Trio. A randomized controlled trial of Cala One showed mixed results, with improvements on some tremor measures, but no improvements on others. However, self-rated improvements on activities of daily living were 50% in the treatment group and 27% in the control group.
Functional electrical stimulation
In this type of system, electrical stimulation is applied to the skin’s surface to stimulate the motor nerves which carry information from the brain to the muscles to trigger muscle contractions. A number of these systems are under development, and some are closer to market in Europe than they are in the US.
Energy dissipation
In this type of system the device contains elements which absorb the extra energy created by the tremor to dampen the movement of the tremor. These systems are purely mechanical and do not need an electrical supply. There are three systems that utilize this type of approach, and all are available for purchase. There are no published clinical trial data yet for these devices, although the manufacturers report that their internal testing demonstrates efficacy. Other energy dissipation systems are under development as well. The three systems that are currently available are:
Tremelo – this system uses a technology called tuned mass damper technology in which springs are attached to weights embedded in a wearable sleeve. As the arm tremors, the spring makes the mass move back and forth, which acts to counteract the tremor. This system (which is similar to systems that stabilize skyscrapers and bridges from wind and earthquakes) thereby dampens the energy of the tremor.
Steadi-Two (Steadi-One was the first version of this system) — uses magnetic tuned mass damper technology to reduce tremor. In this system, a disc surrounded by magnets is embedded in a sleeve, worn on the wrist. Whenever the hand moves in one direction due to tremor, the disc, which moves with the hand, is repelled by the magnet next to it, thereby counteracting the movement of the tremor.
Readi-Steadi® — is a customizable weighted glove which can help dissipate tremor.
Active orthoses
In these systems a wearable device contains elements that sense the tremor and then exert an active force to counteract the tremor. A number of these systems are under development.
Gyroscope stabilization
In this system, gyroscopes are used to counteract the forces generated by tremor. The GyroGloveTM uses multiple miniature gyroscopes in a wearable glove. It is currently under development and cannot be purchased yet.
Eating utensils to dampen tremor
In addition to devices worn directly on the wrist, utensils have been designed to help people with tremor eat more easily. As a rule, weighted utensils can help to dampen tremor and many of these types of products are available for purchase.
Liftware SteadyTM and Gyenno Spoon are two such products and they work by generating movement of the utensil in the direction opposite of the detected tremor. So far there is a small amount of clinical trial evidence supporting the use of Liftware.
Are Wearable Devices for Tremor Worth Trying?
In general, wearable devices for tremor suppression have minimal to low risk of side effects and may be good options for some people whose tremors are not well controlled with medication (having had DBS surgery limits a person’s use of the tremor suppression systems that utilize electrical stimulation, such as Cala Trio). If you are interested in trying a wearable tremor suppression device, talk with your doctor to determine if one of these options may be a good choice for you.
We anticipate that additional clinical trial data will help us better understand the potential of these devices in the treatment plan of Parkinson’s disease tremor. We look forward to more research in this area and more devices coming to the market so that people living with PD can have more effective, and hopefully affordable, options to help them live life to the fullest despite their PD tremors.
Tips and Takeaways
- For some people who do not have good tremor control from their PD medications, talk with your doctor about the potential of using a wearable device that may help control tremor.
- Only one device is currently FDA-approved, with data on its efficacy collected in a randomized clinical trial. Most devices are not FDA-approved, and their use is not yet supported by clinical trials.
- However, the risks of use are very low, and many manufacturers will allow you to return their devices for a full or partial refund if they are not effective for you.